Microphone package

ABSTRACT

A microphone includes a housing including a substrate and a cover disposed over the substrate, the housing including a sound port between the interior of the housing and the exterior of the housing. The microphone also includes a microelectromechanical systems (MEMS) transducer and an integrated circuit (IC) positioned within the housing and mounted on a common surface of the housing, where the MEMS transducer is electrically connected to the IC, and the IC is electrically connected to a conductor on the substrate. The microphone further includes an encapsulating material covering the IC, and an encapsulating material confinement structure disposed between the MEMS transducer and the IC, where the encapsulating material confinement structure at least partially confines the encapsulating material around the IC.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of co-pending U.S. patentapplication Ser. No. 16/128,489, filed Sep. 11, 2018, entitled“Microphone Package.” U.S. patent application Ser. No. 16/128,489 claimsbenefit under § 119(e) to U.S. Provisional Patent Application No.62/557,613, filed Sep. 12, 2017, entitled “Microphone Package,” and is acontinuation-in-part of U.S. patent application Ser. No. 15/988,983,filed May 24, 2018, entitled “Microphone Package for Fully EncapsulatedASIC and Wires,” and issued as U.S. Pat. No. 10,547,955, which claimsbenefit under § 119(e) to U.S. Provisional Patent Application No.62/511,221, filed May 25, 2017, entitled “Microphone Package for FullyEncapsulated ASIC and Wires.” The entire contents of each of the abovementioned applications are incorporated herein by reference.

BACKGROUND

In a micro electro mechanical system (MEMS) microphone, a MEMS dieincludes at least one diaphragm and at least one back plate. The MEMSdie is supported by a base or substrate and enclosed by a housing (e.g.,a cup or cover with walls). A port may extend through the substrate (fora bottom port device) or through the top of the housing (for a top portdevice). Sound energy traverses through the port, moves the diaphragm,and creates a changing electrical potential of the back plate, whichcreates an electrical signal. Microphones are deployed in various typesof devices such as personal computers, cellular phones, mobile devices,headsets, and hearing aid devices.

SUMMARY

In an aspect of the disclosure a microphone includes a housing includinga substrate and a cover disposed over the substrate, the housingincluding a sound port between the interior of the housing and theexterior of the housing. The microphone also includes amicroelectromechanical systems (MEMS) transducer and an integratedcircuit (IC) positioned within the housing and mounted on a commonsurface of the housing, where the MEMS transducer is electricallyconnected to the IC, and the IC is electrically connected to a conductoron the substrate. The microphone further includes an encapsulatingmaterial covering the IC, and an encapsulating material confinementstructure disposed between the MEMS transducer and the IC, where theencapsulating material confinement structure at least partially confinesthe encapsulating material around the IC.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the following drawings and thedetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present disclosure will becomemore fully apparent from the following description and appended claims,taken in conjunction with the accompanying drawings. Understanding thatthese drawings depict only several embodiments in accordance with thedisclosure and are, therefore, not to be considered limiting of itsscope, the disclosure will be described with additional specificity anddetail through use of the accompanying drawings.

FIG. 1 is a representation of a cross-sectional view of first examplemicrophone device according to embodiments of the present disclosure.

FIG. 2 is a representation of a cross-sectional view of a second examplemicrophone device according to embodiments of the present disclosure.

FIG. 3 is a representation of a cross-sectional view of a third examplemicrophone device according to embodiments of the present disclosure.

FIG. 4A is a representation of a cross-sectional view of a fourthexample microphone device according to embodiments of the presentdisclosure.

FIG. 4B shows an expanded view of a portion of the fourth examplemicrophone device shown in FIG. 4A.

FIG. 5 is a representation of a cross-sectional view of a fifth examplemicrophone device according to embodiments of the present disclosure.

FIG. 6A is a representation of a top view of a seventh examplemicrophone device according to embodiments of the present disclosure.

FIG. 6B shows an isometric view of a portion of the seventh examplemicrophone device shown in FIG. 6A.

FIG. 7A is a cross-sectional view of a seventh example microphone deviceaccording to an embodiment of the present disclosure.

FIG. 7B depicts a top view of the seventh example microphone deviceshown in FIG. 7A.

FIG. 7C shows a cross-sectional view of the seventh example microphonedevice shown in FIG. 7A having more than one IC.

FIG. 8 shows a cross-sectional view of a eighth example microphonedevice according to an embodiment of the present disclosure.

FIG. 9 shows a flow diagram of an example process for manufacturing amicrophone device according to an embodiment of the present disclosure.

FIGS. 10A and 10B depict a cross-sectional view and a top view,respectively, of a ninth example microphone device according to anembodiment of the present disclosure.

FIG. 11 shows a flow diagram of an example process for manufacturing amicrophone device according to an embodiment of the present disclosure.

FIG. 12 shows a cross-sectional view of a tenth example microphonedevice according to an embodiment of the present disclosure.

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. The illustrative embodiments described in thedetailed description, drawings, and claims are not meant to be limiting.Other embodiments may be utilized, and other changes may be made,without departing from the spirit or scope of the subject matterpresented here. It will be readily understood that the aspects of thepresent disclosure, as generally described herein, and illustrated inthe figures, can be arranged, substituted, combined, and designed in awide variety of different configurations, all of which are explicitlycontemplated and make part of this disclosure.

DETAILED DESCRIPTION

The present disclosure describes devices and techniques for improvingrobustness of microphone devices and pressure-sensing transducers, suchas those incorporating microelectromechanical systems (MEMS)transducers. In some embodiments, the devices and techniques describedin the present disclosure improve a signal-to-noise ratio of a top-portmicrophone device by including an embedded cavity within a substrate. Aheight of the substrate can be greater than a height of a cover whichincludes the acoustic port.

In one or more embodiments, the microphone device can include anencapsulating material at least partially covering an integrated circuitelectrically connected to the MEMS transducer, and the cover can includea thin region positioned above the encapsulating material. The thinregion provides additional area to accommodate the encapsulatingmaterial without having to increase the height of the cover or increasethe front volume (discussed below) of the enclosure which couldnegatively impact electro-acoustic performance.

In one or more embodiments, the microphone device can include a sealedport positioned under the integrated circuit. During manufacturing, thesealed port can aid in removing debris trapped in the embedded cavity inthe substrate.

In one or more embodiments, the microphone device can include amultilayered substrate, in which electrical components such as resistorsand capacitors can be formed. By forming the components within thesubstrate instead of on a top surface of the substrate, the overall sizeof the microphone device can be reduced.

In one or more embodiments, a particulate filter can be positionedbetween the MEMS transducer and an opening to the embedded cavity. Theparticulate filter can reduce the risk of debris trapped in the embeddedcavity from making contact with a diaphragm of the MEMS transducer,thereby improving the reliability of the microphone device.

In one or more embodiments, the microphone device can include a coverbonding ring for bonding the cover to the substrate. The cover bondingring can include a notch or a cut-out which can be filled with anadhesive, such as epoxy, to reduce the risk of the cover gettingdetached from the substrate during manufacturing or installation of themicrophone device.

In one or more embodiments, the microphone device includes a surfacecavity which accommodates the integrated circuit and the encapsulatingmaterial, thereby reducing the risk of the encapsulating material makingcontact with the MEMS transducer during manufacture. In one or moreembodiments, the microphone device can include a platform on which theMEMS transducer can be placed, so as to isolate the MEMS transducer fromthe encapsulating material.

FIG. 1 is a cross-sectional view of first example microphone device 100according to an embodiment of the present disclosure. The first examplemicrophone device 100 includes a substrate 110, a microelectromechanicalsystems (MEMS) transducer 102, a first integrated circuit (IC) 104, asecond IC 106, and a cover 108. The substrate 110 includes first surface(a front surface 116) and an opposing second surface (a back surface114). The MEMS transducer 102 and the first IC 104 are disposed on thefront surface 116 of the substrate 110, while the second IC 106 isdisposed on a top surface of the first IC 104. Wires 124 electricallyconnect the MEMS transducer 102 to the first IC 104. While not shown,wires can also connect the MEMS transducer 102 to the second IC 106. Inaddition, wires can also connect each of the MEMS transducer 102, thefirst IC 104, and the second IC 106 to the substrate 110. The MEMStransducer 102, the first IC 104, the second IC 106, and the substrate110 can each include conductive bounding pads to which ends of the wirescan be bonded. In some embodiments, wires 124 can be bonded to theappropriate bonding pads using a solder.

The cover 108 can be affixed on the front surface 116 of the substrate110 to enclose and protect the MEMS transducer 102, the first IC 104,the second IC 106, and any bonding wires. The cover 108 can includematerials such as plastic or metal. The cover 108 can define a throughhole or a top port 122 that extends between an outer top surface 118 andan inner top surface 126 of the cover 108. The cover 108 can have acover height H_(c) defined by a distance of the outer top surface 118from the front surface 116 of the substrate 110. In someimplementations, the cover height H_(c) can be about 0.3 mm to about 0.7mm, or about 0.4 mm to about 0.6 mm, or about 0.55 mm. The cover 108 canhave a thickness T_(c) defined by a distance between the outer topsurface 118 and the inner top surface 126. In some implementations, thethickness of the cover 108 can be uniform, while in otherimplementations, the thickness of the cover 108 can be non-uniform.Viewed in a direction that is normal to the outer top surface 118 of thecover 108, the cover 108 can have a substantially rectangular, circular,elliptical, or any polygonal shape. The inner top surface 126 of thecover 108, inner side surfaces 128 of the cover 108, and the exposedportions, inside the cover 108, of the front surface 116, the MEMStransducer 102, the first IC 104, and the second IC 106 define a frontvolume 130. The front volume 130, a diaphragm of the MEMS transducer102, and a back volume (discussed below) can, in combination, contributeto the acoustic characteristics of the first example microphone device100.

The substrate 110 can include, without limitation, a printed circuitboard, a semiconductor substrate, or a combination thereof. Thesubstrate 110 can have a substrate height H_(s) defined by the distancebetween the front surface 116 and the back surface 114. In someimplementations, the height H_(s) of the substrate 110 can be about 0.3mm to about 1.8 mm, or about 0.5 mm to about 0.8 mm, or about 0.65 mm.In some implementations, the height H_(s) of the substrate 110 can begreater than the height H_(c) of the cover 108. The substrate 110 candefine an embedded cavity 112 disposed between the front surface 116 andthe back surface 114. The substrate 110 also can define a port 120 thatextends between the front surface 116 and the embedded cavity 112. Theport 120 is positioned below the MEMS transducer 102 such that theembedded cavity 112 is in fluid communication with a diaphragm of theMEMS transducer 102. In some implementations, the substrate 110 candefine one or more ports in addition to the port 120 that extendsbetween the front surface 116 and the embedded cavity 112. Theadditional port or ports, like the port 120, can provide fluidcommunication between the embedded cavity 112 and one or more diaphragmsof the MEMS transducer 102. For example, the MEMS transducer can be amulti-motor MEMS transducer that can include two or more diaphragms. Thesubstrate 110 can define an additional port extending between the frontsurface 116 and the embedded cavity 112, such that the port 120 ispositioned under a first diaphragm and the additional port is positionedunder a second diaphragm of the multi-motor MEMS transducer. In someimplementations, the additional ports, like the port 120, can providefluid communication between the embedded cavity 112 and additional MEMStransducers, like the MEMS transducer 102. As an example, each of theMEMS transducer may include a single diaphragm.

The embedded cavity 112 can have a height H_(cavity), a widthW_(cavity), and a length L_(cavity) (not shown). The height H_(cavity)of the embedded cavity 112 is less than the height H_(s) of thesubstrate 110. In some implementations, the height H_(cavity) of theembedded cavity 112 can be about 60% to about 20%, or about 50% to about30%, or about 40% of the height H_(s) of the substrate 110. A backvolume 138 is formed by the embedded cavity 112, in addition to a volumedefined by the port 120 and a volume defined by the MEMS transducer 102in relation to the front surface 116 of the substrate 110. The frontvolume 130 to back volume 138 ratio can affect the acousticcharacteristics of the first example microphone device 100, such as, forexample, a signal-to-noise ratio (SNR) of the first example microphonedevice 100. For example, reducing the front volume 130 to back volume138 ratio can improve the SNR of the first microphone device. In one ormore embodiments, the front volume 130 to back volume 138 ratio canrange from about 0.5 to about 3.

The MEMS transducer 102 can include a conductive diaphragm positioned ina distance relationship with a conductive back plate. The diaphragm isconfigured to move in relation to the back plate in response to incidentacoustic signals. The movement of the diaphragm in relation to the backplate causes a capacitance associated with the MEMS transducer 102 tovary. The change in the capacitance of the MEMS transducer 102 inresponse to the acoustic signals can be measured and converted into acorresponding electrical signal. The MEMS transducer 102 can include oneor more diaphragms that can move in relation to one or more back plates.

The first IC 104 and the second IC 106 can include analog and/or digitalcircuitry for processing electrical signals received from the MEMStransducer 102. In one or more embodiments, the first IC 104 and thesecond IC 106 can be an integrated circuit packages having a pluralityof pins or bonding pads that facilitate electrical connectivity tocomponents outside of the first IC 104 and the second IC 106 via wires.In particular, the first IC 104 can include bonding pads to which thefirst set of wires 124 can be connected. Bonding pads can also bepresent on the second IC 106 for connecting another set of wires betweenthe MEMS transducer 102 and the second IC 106. The analog or digitalcircuitry can include amplifiers, filters, analog-to-digital converters,digital signal processor, and other electrical circuitry for processingthe electrical signals received from the MEMS transducer 102 and othercomponents on the substrate 110. In some implementations, the second IC106 can include a digital signal processor, while the first IC 104 caninclude additional circuitry. In some implementations, the second IC 106may not be present, and the circuitry that would have been included inthe second IC 106 can instead be included in the first IC 104. The firstIC 104 and the second IC 106 can also include additional bond pads forbonding wires connecting the respective IC to conductors on the frontsurface 116 of the substrate 110 and for bonding wires connecting thefirst IC 104 to the second IC 106. In one or more embodiments, the firstIC 104 and the second IC 106 can have a light sensitivity coating thatblocks light from entering the circuitry inside the IC 104. In one ormore embodiments, one or more bonding pads on the first IC 104, thesecond IC 106, and the substrate 110 can be gold bonding pads. Usinggold bonding pads can improve corrosion resistance due to exposure tomoisture and other environmental substances through the top port 122.Corrosion resistance can be also reduced by coating the bonding padswith an anti-corrosive material.

FIG. 2 is a cross-sectional view of a second example microphone device200 according to an embodiment of the present disclosure. The secondexample microphone device 200 is similar in many respects to the firstexample microphone device 100 discussed above in relation to FIG. 1, andfeatures described herein with respect to FIG. 1 or similar componentsof the other embodiments described herein can be applied to any of thecorresponding components of the various embodiments unless otherwiseindicated. The second example microphone device 200 further includes anencapsulating material 132 and a thin region 134. The encapsulatingmaterial 132 at least partially covers the first IC 104 and the secondIC 106 and/or any wires (not shown) that extend between the first IC104, the second IC 106 and the substrate 110, in some embodiments. Inone or more embodiments, the encapsulating material 132 completelycovers the first IC 104 and the second IC 106 and/or any wires (notshown) that extend between the first IC 104, the second IC 106 and thesubstrate 110. In one or more embodiments, the encapsulating material132 can completely cover the first IC 104 and the second IC 106, and atleast partially cover any wires extending between the first IC 104, thesecond IC 106, and the substrate 110. The encapsulating material 132 canbe a non-conductive material such as epoxy. One process stage during themanufacturing of the second example microphone device 200 can include adeposition of the encapsulating material 132 over the first IC 104 andthe second IC 106.

The encapsulating material 312 can be deposited such that it at leastpartially covers (or in some instances, completely covers) the first IC104, the second IC 106 and wires extending to the substrate 110. Duringdeposition, the encapsulating material 132 can be in a high temperatureand low viscosity state. Over time, the encapsulating material 132 coolsand solidifies to form a covering over the first IC 104, the second IC106 and wires extending to the substrate 110. In some instances, duringdeposition, the low viscosity of the encapsulating material 132 canresult in lateral spreading of the encapsulating material. In some suchinstances, where the first IC 104 and the MEMS transducer 102 aredisposed on the same front surface 116 of the substrate 110, the lateralspreading of the encapsulating material 132 may result in theencapsulating material 132 making contact with the MEMS transducer 102.This may damage or adversely impact electro-acoustic performance of theMEMS transducer 102. In one or more embodiments, in addition to, orinstead of, an encapsulating material 132, the first IC 104 and thesecond IC 106 can have a light sensitivity coating that blocks lightfrom entering the circuitry inside the IC 104. In one or moreembodiments, one or more bonding pads on the first IC 104, the second IC106, and the substrate 110 can be gold bonding pads. Using gold bondingpads can improve corrosion resistance due to exposure to moisture andother environmental substances through the top port 122. Corrosionresistance can be also reduced by coating the bonding pads with ananti-corrosive material.

To reduce the risk of damage to the MEMS transducer 102, the frontsurface 116 of the substrate 110 can have a cavity (not shown) formed inthe front surface 116 of the substrate 110, and the first IC 104, thesecond IC 106, and the encapsulating material 132 can be partially orwholly disposed within the cavity. The lateral spreading of theencapsulating material 132, during and after deposition, can be confinedto within the sidewalls of the cavity. Thus, the MEMS transducer 102 andother components mounted on the substrate 110 can be protected fromundesirable contact with the encapsulating material 132.

The thin region 134 can be formed on the cover 108 near the top port122. The thin region 134 can include a stepped inner top surface 136,which is stepped, or indented, in relation to the inner top surface 126.In particular, the stepped inner top surface 136 is stepped in thedirection of the outer top surface 118. A distance between the steppedinner top surface 136 and the outer top surface 118 defines a thinregion 134 thickness T_(tr), which is less than the thickness T_(c) ofthe cover 108 defined by the distance between the inner top surface 126and the outer top surface 118. In some implementations, the thicknessT_(tr) of the thin region 134 can be about 30% to about 70% of thethickness T_(c) of the cover 108, or about 40% to about 60% of thethickness T_(c) of the cover 108, or about 50% of the thickness T_(c) ofthe cover 108. The thin region 134 can be formed along a periphery ofthe top port 122. The stepped inner top surface 136 can have a perimeterthat forms at least a portion of a perimeter of the top port 122. Insome implementations, the stepped inner top surface 136 can entirelysurround the top port 122. In some implementations, the thin region 134can be positioned near the top port 122 such that the perimeter of thethin region 134 is separated from the perimeter of the top port 122. Theshape of the perimeter of the thin region 134, when viewed in adirection normal to the inner top surface 126, can be any regular orirregular polygonal shape, or curved shape. The reduced thickness of thecover 108 at the thin region 134 allows clearance to accommodate theencapsulating material 132 disposed on the substrate 110 without havingto increase the height H_(c) of the cover 108, and thereby increasingthe front volume 130. The second example microphone device 200 also canincorporate indented portions in the cover 108 and other features of amicrophone device discussed in the commonly owned U.S. patentapplication Ser. No. 15/154,545, the subject matter of which isincorporated herein by reference in its entirety.

FIG. 3 is a cross-sectional view of a third example microphone device300 according to an embodiment of the present disclosure. The thirdexample microphone device 300 is similar in many respects to the secondexample microphone device 200 discussed above in relation to FIG. 2. Tothe extent that some features of the third example microphone device 300are similar to those of the second example microphone device 200, suchfeatures are provided with the same reference numerals in both FIGS. 2and 3. The third example microphone device 300 further includes a sealedport 140. As discussed above, the front surface 116 defines the port 120(and any additional ports), which extends between the front surface 116and the embedded cavity 112 and is positioned under the MEMS transducer102. The front surface 116 also defines the sealed port 140, which alsoextends between the front surface 116 and the embedded cavity 112.However, unlike the port 120, which is disposed under the MEMStransducer 102, to provide fluid communication between the diaphragm andthe embedded cavity 112, the sealed port 140 is instead positionedoutside of a perimeter of the MEMS transducer formed on the frontsurface 116.

The sealed port 140 can be positioned, for example, under the first IC104, such that the sealed port 140 is covered by the first IC 104. Insome instances, a dispensed die attach or preferably die attach film 142may be used to adhere the first IC 104 to the front surface 116 of thesubstrate 110. The die attach film 142 can include an adhesive that canaid in bonding the first IC 104 to the front surface 116. In some suchinstances, the die attach film 142 can be used to cover and seal thesealed port 140. The sealed port 140 can aid in removing debrisdeposited within the embedded cavity 112 during manufacturing. Forexample, during the formation of the embedded cavity 112 or otherfeatures of the substrate 110, debris may get trapped in the embeddedcavity 112. This debris, if not removed from the embedded cavity 112,may come in contact with the diaphragm of the MEMS transducer 102,resulting in an increased risk of damage to the MEMS transducer 102. Theformation of the sealed port 140 in the substrate 110 (prior to theplacement of the first IC 104 or the die attach film 142) can aid inremoving the debris from the embedded cavity 112. For example, air canbe blown through one of the port 120 and the sealed port 140 to allowdebris to be flushed out via the other of the port 120 and the sealedport 140. Once the debris is removed, the first IC 104 or the die attachfilm 142 can be positioned over the front surface 116 to seal the sealedport 140. In some implementations, the sealed port 140 can be completelysealed from the front volume 130. In some other implementations, thesealed port 140 may be partially sealed from the front volume 130. Thesealed port 140 may not contribute to the acoustic characteristics ofthe third example microphone device 300. As mentioned above, thesubstrate can define one or more ports positioned under the MEMStransducer 102 to correspond to one or more diaphragms. The sealed port140 can be provided under the first IC 104 in addition to the one ormore ports provided under the MEMS transducer 102.

FIG. 4A is a cross-sectional view of a fourth example microphone device400 according to an embodiment of the present disclosure. The fourthexample microphone device 400 is similar in many respects to the secondexample microphone device 200 discussed above in relation to FIG. 2. Tothe extent that some features of the third example microphone device 300are similar to those of the second example microphone device 200, suchfeatures are provided with the same reference numerals in both FIGS. 2and 4A. The fourth example microphone device 400 includes a multilayeredsubstrate 410. The multilayered substrate 410, similar to the substrate110 shown in FIG. 2, defines an embedded cavity 112 and a port 120. Themultilayered substrate 410 additionally includes multiple layers ofmaterials, and electronic components such as resistors and capacitors.

FIG. 4B shows an expanded view of a portion 420 of the fourth examplemicrophone device 400 shown in FIG. 4A. The multilayered substrate 410includes a top substrate layer 430, an inner substrate layer 416, and abottom substrate layer 424. The top substrate layer 430, the innersubstrate layer 416, and the bottom substrate layer 424 can includematerials such as epoxy, glass-reinforced epoxy, composite fiberglasscloth with epoxy resin (e.g., FR4), and the like. The multilayeredsubstrate 410 can define a plated through-hole 432, which can be filledwith a solder mask 408. In one or more embodiments, the platedthrough-hole 432 can be plated with conductive materials, such as copperor aluminum. A first adhesive layer 414 can be disposed between the topsubstrate layer 430 and the inner substrate layer 416, and a secondadhesive layer 418 can be disposed between the inner substrate layer 416and the bottom substrate layer 424. A top metal layer 406 can bedisposed over the top metal layer 406 on a side of the top substratelayer 430 that is opposite to the side of the top substrate layer 430that is adjacent to the inner substrate layer 416. The solder mask 408can cover at least a portion of the top metal layer 406. A bottom metallayer 426 can be disposed on the bottom substrate layer 424 on a side ofthe bottom substrate layer 424 that is adjacent to the inner substratelayer 416. The solder mask 408 also can cover at least a portion of thebottom metal layer 426. A through-hole metal layer 434 can extendthrough the plated through-hole 432 between the top metal layer 406 andthe bottom metal layer 426, forming an electrical connectiontherebetween.

The multilayered substrate 410 also includes several inner metal layers,such as the first inner metal layer 412 disposed between the topsubstrate layer 430 and the inner substrate layer 416, and a secondinner metal layer 428 and a third inner metal layer 422 disposed betweenthe inner substrate layer 416 and the bottom substrate layer 424. Thesecond inner metal layer 428 and the third inner metal layer 422 can beseparated by a dielectric layer 436. The third inner metal layer 422 canmake contact with the through-hole metal layer 434, thereby makingelectrical contact with the top metal layer 406 and the bottom metallayer 426. In some implementations, the first inner metal layer 412 canbe used as a ground terminal, and the second and third inner metallayers 428 and 422 can be used for carrying electrical signals.

The multilayered substrate 410 also can include passive electricalcircuit elements such as resistors and capacitors. For example, aresistor 404 can be disposed on the same side of the top substrate layer430 on which the top metal layer 406 is disposed. One end or terminal ofthe resistor 404 can form an electrical contact with the top metal layer406. The resistor 404 can include conductive materials having anelectrical resistance that is substantially greater than an electricalresistance of the top metal layer 406. The multilayered substrate 410also can include a reactive electrical circuit element such as acapacitor 402 disposed between the inner substrate layer 416 and thebottom substrate layer 424. The capacitor 402 can be include a portionof the dielectric layer 436 disposed between a portion of the secondinner metal layer 428 and a portion of the third inner metal layer 422.The portion of the second inner metal layer 428 can form a firstterminal of the capacitor 402, while the portion of the third innermetal layer 422 can form a second terminal of the capacitor 402. Thesecond terminal of the capacitor 402 can be coupled to the resistor viathe through-hole metal layer 434 and the top metal layer 406.

The locations of the resistor 404 and the capacitor 402 shown in FIG. 4Bare only examples. The resistor 404 and the capacitor 402 can be locatedelsewhere within the multilayered substrate 410 as well. For example,the capacitor 402 can be alternatively disposed between the topsubstrate layer 430 and the inner substrate layer 416, or adjacent toany of the layers of the multilayered substrate 410. The resistor 404also may be located adjacent to any of the layers of the multilayeredsubstrate 410. While not shown in FIG. 4B, the multilayered substrate410 can include additional resistors and capacitors, similar to theresistor 404 and the capacitor 402, having various values. In one ormore embodiment, the values of the resistor 404 or the additionalresistors can range from about 10 ohms to about 100 ohms. In one or moreembodiments, the resistor 404 or the additional resistors can have asize in the range of about 75 micrometers to about 150 micrometers inwidth and the range of about 75 micrometers to about 300 micrometers inlength. In one or more embodiments, the thickness of the resistor 404 orthe additional resistors can be in the range of about 0.1 micrometer toabout 1 micrometer. In one or more embodiments, the values of thecapacitor 402 or the additional capacitors can range from about 10 pF toabout 300 pF. By forming resistors and capacitors in one or more layersof the multilayered substrate 410, these electrical components, whichwould have otherwise been disposed over the front surface 116, can nowbe accommodated within the multilayered substrate 410 itself, resultingin a reduction in radio frequency (RF) interference caused by theseelectrical components. In some instances, an additional benefit ofaccommodating these electrical components within the multilayeredsubstrate 410 can be freeing up of space on the front surface 116 toaccommodate other components or resulting in a reduction in the overallsize of the fourth example microphone device 400.

FIG. 5 is a cross-sectional view of a fifth example microphone device500 according to an embodiment of the present disclosure. The fifthexample microphone device 500 is similar in many respects to the secondexample microphone device 200 discussed above in relation to FIG. 2. Tothe extent that some features of the fifth example microphone device 500are similar to those of the second example microphone device 200, suchfeatures are provided with the same reference numerals in both FIGS. 2and 5. The fifth example microphone device 500 can include a particulatefilter 502 disposed adjacent the port 120. As mentioned above inrelation to the third example microphone device 300 in relation to FIG.3, manufacturing process of the substrate can result in accumulation ofdebris within the embedded cavity 112. This debris can increase the riskof damage to the diaphragm of the MEMS transducer 102. The particulatefilter 502 reduces the risk of the debris in the embedded cavity 112making contact with the diaphragm of the MEMS transducer 102. Theparticulate filter 502 can include perforations having sizes that aresufficiently large such that the particulate filter 502 does not impedethe fluid communication between the diaphragm and the embedded cavity112, but having sizes that are sufficiently small so as to impede debriswithin the embedded cavity 112 from making contact with the diaphragm.In one or more embodiments, the particulate filter 502 can be comprisedof porous ceramic with an effective pore size ranging from about 10 toabout 20 micrometers and a porosity between 55 to 65%. Other pore sizesand porosities can also be selected that allow sufficient filtering ofdebris while maintaining acceptable acoustic transparency of theparticulate filter 502. While the particulate filter 502 is shown inFIG. 5 as being disposed on the end of the port 120 that is adjacent tothe MEMS transducer 102, the particulate filter 502 can alternatively bedisposed on the opposite end of the port 120. That is, the particulatefilter 502 can be positioned to cover the end of the port 120 that opensinto the embedded cavity 112.

In some implementations, an additional particulate filter can bepositioned to cover the top port 122. The top port particulate filtercan reduce the risk of debris entering the front volume 130 via the topport 122. The top port particulate filter can be positioned under thetop port 122, over the top port 122 or flush within the top port 122,such that a top surface of the top port particulate filter is flushwith, or in the same plane as, the outer top surface 118.

FIG. 6A is a top view of a sixth example microphone device 600 accordingto an embodiment of the present disclosure. The top view in FIG. 6A isshown without a cover. FIG. 6B shows an isometric view of a portion ofthe sixth example microphone device 600 shown in FIG. 6A. The sixthexample microphone device 600 includes a substrate 610 having a frontsurface 616. A first IC 104 and a MEMS transducer 102 are disposed onthe front surface 616. The substrate 610 can be similar to the substrate110 discussed above in relation to FIG. 1. A cover bonding ring 650 isalso disposed on the front surface 616. The cover bonding ring 650 has aperimeter that is substantially similar to a perimeter of a cover 656,shown in FIG. 6B. The cover bonding ring 650 can improve the adhesion ofthe cover 656 to the front surface 616 of the substrate 610. Theimproved adhesion reduces the risk of the cover 656 becoming dislodgedor separated from the substrate 610 and exposing the MEMS transducer102, the first IC 104 and other components on the front surface 616. Insome implementations, the cover bonding ring 650 can include a metalmaterial (e.g., a ferrous metal, a non-ferrous metal, copper, steel,iron, silver, gold, aluminum, titanium, etc.). By way of example, thecover bonding ring 650 may include a copper trace that is nickel and/orgold plated (e.g., gold plated over nickel plating, etc.). Such a metalcover bonding ring 650 may be soldered to the front surface 616. Inother embodiments, the cover bonding ring 650 may be formed of anothermaterial (e.g., a thermoplastic material, a ceramic material, etc.). Insome embodiments, the cover bonding ring 650 is adhered, fused, and/orotherwise coupled to the front surface 616 without the use of solder(e.g., adhesively coupled thereto, etc.).

To provide additional mechanical strength to the bonding between thecover 656 and the front surface 616, an under-fill adhesive 658 isdisposed between the cover 656 and the front surface 616. The under-filladhesive 658 is disposed in a space defined by a notch 652 (FIG. 6A)formed in the cover bonding ring 650. The notch 652 includes a notchedsurface 660 that is stepped in relation to an outer side surface 654 ofthe cover bonding ring 650 in a direction towards an inner side surface662 of the cover bonding ring 650. The notched surface 660 issubstantially parallel to the outer side surface 654. A length of thenotched surface 660 in a direction that is substantially normal to alongitudinal axis of the cover 656 and within the plane of the frontsurface 616 is denoted by L_(n). A width of the notch 652 in a directionthat is along the longitudinal axis of the cover and within the plane ofthe front surface 616 is denoted by W_(n). The width W_(n) of the notchdefines a distance between the notched surface 660 and the outer sidesurface 654. The width W_(n) of the notch is less than the width W_(r)of the cover bonding ring 650. This allows a portion of the coverbonding ring 650 to serve as a barrier, and reduce the risk of theunder-fill adhesive 658 bleeding into the portion of the microphonedevice 600 covered by the cover 656, and damaging the internalcomponents, such as the first IC 104, the MEMS transducer 102 or bondingwires 124. While FIGS. 6A and 6B show the notched cover bonding ring 650in relation a top port design, the notched cover guard ring can also beused in bonding the cover 608 to the front surface 616 of the bottomport sixth example microphone device 600 shown in FIG. 6.

In some implementations, the notch 652 can be replaced with a gap,aperture, cut-out, or a vent, resulting in the cover bonding ring 650being non-uniform or discontinuous. During production, the MEMStransducer 102, the cover bonding ring 650, and the cover 656 can besoldered or otherwise coupled to the substrate 610. After the MEMStransducer 102, the cover bonding ring 650, and the cover 656 arecoupled together, a non-meltable adhesive or sealant in the form of anepoxy or another non-meltable material can be applied between thesubstrate 610, the cover bonding ring 650, and the cover 656 toeffectively seal the aperture and isolate the MEMS transducer 102 withinthe cover 656. The epoxy and/or another non-meltable material mayadvantageously have a melting point higher than the solder used tocouple the cover 656 and/or the cover bonding ring 650 to the substrate610 such that the epoxy or another non-meltable material does not meltupon reflow. As a result, when the microphone device 600 is subsequentlyreflowed during integration or installation into a larger device (e.g.,for a smartphone, a tablet, a laptop, a smart watch, a hearing aid, avideo camera, a communications device, etc.), the epoxy or anothernon-meltable material maintains the cover 656 and/or the cover bondingring 650 in position and does not allow the cover 656 and/or the coverbonding ring 650 to tilt, rotate, shift, or otherwise deform during theheating cycle. The sixth example microphone device 600 also canincorporate a tag, a guard ring, and other features of a microphonedevice as discussed in the commonly owned U.S. Patent Application No.62/367,531, the subject matter of which is incorporated herein byreference in its entirety.

FIG. 7A is a cross-sectional view of a seventh example microphone device700 according to an embodiment of the present disclosure. In particular,the seventh example microphone device 700 includes a bottom port designwhere a substrate 710, instead of a cover 708, defines a bottom port 720that allows acoustic signals to be incident on the diaphragm of the MEMStransducer 102. The substrate 710 includes a first surface or a frontsurface 716 and an opposing second surface or back surface 714. The MEMStransducer 102 and the first IC 104 are disposed on the front surface716. Wires 124 can extend from the MEMS transducer 102 to the first IC104. A second set of wires 125 can extend from the first IC to thesubstrate 710. An encapsulating material 132 is disposed over the firstIC 104 to at least partially cover the first IC 104 and the wires 125.In one or more embodiments, the encapsulating material 132 completelycoves the IC 104, while at least partially covering the wires 125. TheMEMS transducer 102, the first IC 104, and the wires 124 are similar tothe corresponding elements with similar reference numerals discussedabove in relation to the first example microphone device 100 shown inFIG. 1. In some implementations, the seventh example microphone device700 can include a second IC (similar to the second IC 106 shown inFIG. 1) disposed over the first IC 104 and covered with theencapsulating material 132. Additional wires can extend between thesecond IC and the first IC 104 and the substrate 710.

The substrate 710 defines the bottom port 720, which includes an openingthat extends between the front surface 716 and the back surface 714 suchthat the outside of the seventh example microphone device 700 is influid communication with the diaphragm of the MEMS transducer 102. Acover 708 is disposed over the front surface 716 of the substrate 710and encloses the MEMS transducer 102, the first IC 104 and the wires 124and 125. Unlike the cover 108 discussed above in relation to the firstexample microphone device 100, shown in FIG. 1, the cover 708 of theseventh example microphone device 700 does not include an opening. Thus,an inner top surface 726 of the cover 708, inner side surfaces 728 ofthe cover 708, and the exposed portions, inside the cover 708, of thefront surface 716, the MEMS transducer 102, and the first IC 104 definea back volume 732 of the seventh example microphone device 700. Theseventh example microphone device 700 also defines a front volume 730,which is a combined volume of a space under the MEMS transducer 102 anda volume defined by the bottom port 720.

The substrate 710 can define an encapsulating material confinementstructure, which can include a surface cavity 750 in the front surface716 of the substrate 710. The surface cavity 750 may extend from a frontsurface 716 of the substrate 710 to an IC mounting surface 754 of thesubstrate 710. In the illustrated embodiment, the front surface 716 andthe IC mounting surface 754 are on separate planes. In some embodiments,the front surface 716 and the IC mounting surface 754 may be in the sameplane; for example, in some embodiments, the MEMS transducer 102 may bemounted on a raised platform, such as in the manner described in furtherdetail below, and the front surface 716 and the IC mounting surface 754may be in the same plane. The first IC 104 is positioned on the ICmounting surface 754 of the surface cavity 750. In some embodiments, thefirst IC 104 is mounted on the IC mounting surface 754 using a bindingmaterial such as solder or glue. While not shown in FIG. 1, the ASICmounting surface can include one or more conductive bonding pads toprovide a connection between conductive traces on the substrate and theIC 104. The second set of wires 125 connect the bonding pads on the ICmounting surface 754 to the bonding pads on the IC 104. In someembodiments, a height H1 of the surface cavity 750 (i.e., a height fromthe IC mounting surface 754 to the front surface 716) can be less thanthe height of the IC 104, such that a portion of the IC 104 extendsabove the cavity.

The substrate 710 also includes a platform 756 (also referred to as “aMEMS mounting surface”) that is raised up above or elevated in relationto the front surface 716. In the illustrated embodiment, the height H1of the surface cavity 750 is greater than a height H2 by which theplatform 756 is raised above the front surface 716. In some embodiments,the height H2 may be greater than or equal to the height H1. Theplatform 756 can be formed around the perimeter of the surface cavity750. In some embodiments, the platform 756 can form a sidewall of thesurface cavity 750. In some other embodiments, the platform 756 can beseparated from the surface cavity 750 by the front surface 716. The MEMStransducer 102 is mounted on a top surface of the platform 756. Thebottom port 720, discussed above, extends through the substrate 710 at aposition where the MEMS transducer 102 is mounted.

The encapsulating material 132 at least partially covers the IC 104and/or the second set of wires 125, and, in some embodiments, completelycovers both the IC 104 and the second set of wires 125. Theencapsulating material 132 can be a non-conductive material such asepoxy. One process stage during the manufacturing of the first examplemicrophone device 100 can include the deposition of the encapsulatingmaterial 132 over the IC 104. The encapsulating material 132 can bedeposited such that it at least partially covers (or in some instancescompletely covers) the IC 104 and the second set of wires 125 thatextend from the IC 104 to the substrate 710. In one or more embodiments,the encapsulating material 132 completely coves the IC 104, while atleast partially covering the wires 125. During deposition, theencapsulating material 132 can be in a high temperature and lowviscosity state. Over time, the encapsulating material 132 cools andsolidifies to form a covering over the IC 104 and the second set ofwires 125. But during deposition, the low viscosity of the encapsulatingmaterial 132 can result in lateral spreading of the encapsulatingmaterial. In instances where the IC 104 and the MEMS transducer 102 aredisposed on the same surface of the substrate 710, the lateral spreadingof the encapsulating material 132 may result in the encapsulatingmaterial 132 making contact with the MEMS transducer 102. This maydamage the MEMS transducer 102. By placing the IC 104 and the second setof wires 125 within the surface cavity 750, the lateral spreading of theencapsulating material 132, during and after deposition, is confined towithin the sidewalls of the surface cavity 750. Thus, the MEMStransducer 102, and other components mounted on the substrate 710, canbe protected from undesirable contact with the encapsulating material132.

After the encapsulating material 132 solidifies, its upper surface canform a curvature that encloses the IC 104 and the second set of wires125. In some embodiments, a height of the encapsulating material 132 canbe represented by a greatest distance between a point on a top surfaceof the encapsulating material 132 and the IC mounting surface 754. Insome embodiments, the height of the encapsulating material 132 can beequal to or greater than a greatest distance that the second set ofwires 125 or the IC 104 extend from the IC mounting surface 754.

The platform 756 provides additional protection from the encapsulatingmaterial 132. That is, mounting the MEMS transducer 102 on the platform756 further isolates the MEMS transducer 102 from the encapsulatingmaterial 132. In some embodiments, a height of the platform 756 can bebased on the volume of encapsulating material 132 to be deposited to atleast partially cover (or in some instances completely cover) the IC 104and the second set of wires 125, and the available volume within thesurface cavity 750.

FIG. 7B depicts a top view of the seventh example microphone device 700shown in FIG. 7A. In particular, the top view is shown without the cover708. The encapsulating material 132 at least partially covers the IC 104and the second set of wires 125, which extend from the IC 104 to thesubstrate 710. In one or more embodiments, the encapsulating material132 completely covers the IC 104 and the second set of wires 125. In oneor more embodiments, the encapsulating material 132 completely coversthe IC 104, while at least partially covering the wires 125. Theplatform 756 surrounds the encapsulating material 132, which, in theillustrated embodiment of FIG. 7B, is completely covering the surfacecavity 750 shown in FIG. 7A. The first set of wires 124, which extendbetween the MEMS transducer 102 and the IC 104 are partially covered bythe encapsulating material 132. The front surface 716 of the substrate710 also includes a cover bonding surface 758, which facilitates bondingthe cover 708 with the substrate 710. In the illustrated embodiment, thecover bonding surface 758 is separated from the platform 756 by aportion of the front surface 716 (i.e., such that, front an innerportion of the microphone device 700, the surfaces transition from theplatform 756 to an inner portion of the front surface 716, then to thecover bonding surface 758, and finally to an outer portion of the frontsurface 716). In some embodiments, the cover bonding surface 758 mayextend to the edge of the platform 756 with no intervening portion ofthe front surface 716. In some embodiments, the cover bonding surface758 can be a metal surface that can bond with a metal periphery of thecover 708 using a solder or a glue. The platform 756 not only protectsthe MEMS transducer 102 from the encapsulating material 132, but alsoprotects the cover bonding surface 758 from contact with theencapsulating material 132. This prevents any defect in bonding of thecover 708 to the substrate 710, which may occur if the encapsulatingmaterial 132 were to spill over to the cover bonding surface 758. In oneor more embodiments, the platform 756 may not completely surround thesurface cavity 750. For example, the platform 756 may extend only on oneside of the surface cavity 750 that is adjacent to the MEMS transducer102. In some other embodiments, the platform 756 may extend along acomplete or partial length of one or more sides of the surface cavity750.

FIG. 7C shows a cross-sectional view of the seventh example microphonedevice 700 shown in FIG. 7A having more than one ICs. In particular, theseventh example microphone device 700 shown in FIG. 7C includes a firstIC 104 and a second IC 106, both of which are at least partially coveredby the encapsulating material 132. In one or more embodiments, theencapsulating material 132 completely covers the first IC 104 and thesecond IC 106. In one or more embodiments, the encapsulating material132 can completely cover the first IC 104 and the second IC 106 while atleast partially covering the second set of bonding wires 125. While notshown in FIG. 7C, the seventh example microphone device 700 can includebonding wires in addition to the first set of bonding wires 124 and thesecond set of bonding wires 125 for forming electrical connectionsbetween the MEMS transducer 102, the first IC 104, the second IC 106 andthe substrate 710. At least one of these additional bonding wires can beat least partially covered by the encapsulating material 132. The firstIC 104 and the second IC 106 can be similar to the first IC 104 and thesecond IC 106 discussed above in relation to FIGS. 1A-5.

FIG. 8 shows a cross-sectional view of a eighth example microphonedevice 800 according to an embodiment of the present disclosure. Severalelements of the eighth example microphone device 800 are similar to thecomponents of the seventh example microphone device 700 shown in FIGS.7A and 7B. To that extent, the similar elements have been labeled withsimilar reference numbers. The eighth example microphone device 800 doesnot include a platform. The substrate 802 has a surface cavity 820formed within a front surface 822 of the substrate 802, and a bottomsurface of the surface cavity 820 serves as an IC mounting surface 824.The height H1′ of the surface cavity 820 is greater than the height ofthe IC 104, such that the entirety of the IC 104 falls within a volumeof the surface cavity 820. In some embodiments, the height H1′ can beequal to or greater than the height of IC 104. In still furtherembodiments, the height H1′ can be less than the height of the IC 104.For example, the IC 104 may be taller than the height H1′ of the surfacecavity 820, but the difference in the heights may be sufficiently smallsuch that an encapsulating material 808 does not make contact with theMEMS transducer 102 and/or a cover mounting surface during deposition.By having the height of the surface cavity 820 to be greater than aheight of the IC 104, the risk of spillover of the encapsulatingmaterial 808 during deposition can be reduced while ensuring that theencapsulating material 808 fully covers the IC 104 and at least aportion of the second set of wires 125. The encapsulating material 808can be similar to the encapsulating material 132 discussed above.

The substrate 802 can also include a cover mounting surface (not shown)to facilitate bonding the cover 708 onto the front surface 822 of thesubstrate 202. The cover mounting surface can be similar to the coverbonding surface 758 discussed above in relation to FIG. 7B.

In one or more embodiments, more than one IC can be mounted within thesurface cavity 820. For example, more than one ICs can be disposedside-by-side within the surface cavity 820. In another example, morethan one ICs can be stacked on top of each other. In yet anotherexample, more than one ICs may be both stacked on top of each other anddisposed side-by-side within the surface cavity 820. The encapsulatingmaterial 808 can be deposited in the surface cavity 820 such that it atleast partially covers (or in some instances, completely covers) themore than one ICs regardless of the manner in which they are arrangedwithin the surface cavity 820.

As discussed above in relation to FIGS. 7A-8, the encapsulatingmaterials 132 and 808 at least partially cover the IC 104 and the secondset of wires 125. In one or more embodiments, the encapsulating materialcan completely cover the IC 104 and the second set of wires 125. In oneor more embodiments, the encapsulating material 132 can completely coverthe IC 104 while only partially covering the second set of wires 125.The second set of wires 125 may also be completely covered. By coveringthe IC 104 and the second set of wires 125 within the encapsulatingmaterial 132 or 808, an effect of radio frequency signals, generated bythe IC 104 and the second set of wires 125, on the MEMS transducer 102and other components mounted on the substrate 710 or 802 can be reduced.In some embodiments, partially or completely covering the IC 104 andpartially or completely covering the wires in encapsulating material maycause a substantial reduction in noise in the microphone device ascompared to a microphone device that does not include encapsulatingmaterial or only partially encapsulates an IC. By reducing the radiofrequency interference, a level of noise in the electrical signalsgenerated by the MEMS transducer 102 and the other components on thesubstrate 710 and 802 can be reduced. In some embodiments, animprovement in noise attenuation of about −15 dB is obtained for themicrophone device having an encapsulating material completely coveringthe IC in comparison with a microphone device having no encapsulationmaterial. In instances where the microphone device includes more thanone IC, such as when two ICs are stacked on top of each other, theencapsulating material 132 or 808 can entirely or partially cover all ofthe ICs and wires connecting the ICs to the substrate.

FIG. 9 shows a flow diagram of an example process 900 for manufacturinga microphone device according to the embodiments of the presentdisclosure. The process 900 includes providing a substrate (stage 902),forming an surface cavity on a front surface of the substrate (stage904), mounting a MEMS transducer on the substrate (stage 906), mountingan IC on an IC mounting surface in the surface cavity (stage 908),installing a first set of bonding wires between the IC and the MEMStransducer, and a second set of wires between the IC and the substrate(stage 910), and depositing an encapsulation material into the surfacecavity to at least partially cover (or in some instances, completelycover) the IC and the second set of wires (stage 912). It should benoted that the order of stages described herein is provided by way ofexample only, and the present disclosure is not limited to anyparticular order of performing the stages. For example, in someembodiments, the MEMS transducer may be mounted prior to mounting of theIC, while in other embodiments, the IC may be mounted prior to mountingof the MEMS transducer.

The process 900 includes providing a substrate (stage 902). As discussedabove in relation to FIGS. 7A-8, the substrate can include a printedcircuit board or a semiconductor material. In some embodiments, thesubstrate can be similar to the substrate 710 or the substrate 802 shownin FIGS. 7A-8. The substrate can include a single-layered or amultilayered printed circuit board, where each layer can include a setof conductive traces separated by insulators. The conductive traces canbe patterned based on the locations connectivity of the components, suchas the MEMS transducer and the IC to be mounted on the substrate.

The process 900 further includes creating a surface cavity on a frontsurface of the substrate (stage 904). One example implementation of thisprocess stage is discussed above in relation to FIGS. 7A-8. The surfacecavity 750 is created on a front surface 716 of the substrate 710. Inanother example, as shown in FIG. 8, the surface cavity 820 is formed onthe front surface 822 of the substrate 802. In some embodiments, thecavity in the front surface of the substrate can be created using one ormore of chemical etching, a photoengraving routing, stamping or blankingthrough a substrate layer, and the like. The bottom of the cavity canform an IC mounting surface for mounting an IC. The IC mounting surfacecan include one or more bonding pads that can be connected to bondingpads on the IC using wire bonding. In some embodiments, the process 900also can include forming a ledge or a platform adjacent to the surfacecavity. One example of such a platform is discussed above in relation toFIGS. 7A-8. In one or more embodiments, the platform can be formed byetching the surface of the substrate around the desired location of theplatform. In some other embodiments, the platform can be formed bydepositing additional layers of the substrate at the desired location ofthe platform. In one or more embodiments, the substrate and the platformcan be formed of the same material. In one or more embodiments, thesubstrate and the platform can be formed of different materials. Forexample, materials used for forming the substrate and the platform caninclude materials such as fiberglass, epoxy resin, and solder mask.

The process 900 further includes mounting a MEMS transducer on a frontsurface of the substrate (stage 906) and mounting an IC on an ICmounting surface (stage 908). Example implementations of these processstages are discussed above in relation to FIGS. 7A-8. For example, asshown in FIGS. 7A-8, the MEMS transducer 102 is mounted on the substrate710 or 802, and the IC 104 is mounted on the IC mounting surface 754 or824. The MEMS transducer 102 and the IC 104 can be mounted manually orby machine (e.g., using a “pick and place machine”). In someembodiments, flip-chip techniques also can be used to mount the MEMStransducer 102 and the IC 104.

The process 900 also includes installing a first set of bonding wiresbetween the IC and the MEMS transducer, and a second set of wiresbetween the IC and the substrate (stage 910). Examples of theimplementation of this process stage are discussed above in relation toFIGS. 7A-8. For example, a first set of wires 124 are installed toelectrically connect the MEMS transducer 102 to the IC 104. A second setof wires 125 are installed to electrically connect the IC 104 toconductive traces on the substrate 710. The first set of wires 124 andthe second set of wires 125 can include conductive materials such asaluminum, copper, silver, gold, and the like. The wires can be installedusing techniques such as ball bonding and wedge bonding.

The process 900 additionally includes depositing an encapsulationmaterial into the surface cavity to at least partially cover the IC andthe second set of wires (stage 912). Examples of the implementation ofthis process stage are discussed above in relation to FIGS. 7A-8. Forexample, as shown in FIGS. 7A and 8, the encapsulating material 132 atleast partially or completely covers the IC 104 and the second set ofwires 125. Similarly, as shown in FIG. 8, the encapsulating material 808at least partially or completely covers the IC 104 and the second set ofwires 125. In some embodiments, the encapsulating material can be anepoxy, or materials such as resins, polymers, glass, plastic, and thelike. Before deposition, the encapsulating material can be heated to apredetermined temperature to allow the encapsulating material to flow.The heated epoxy can be deposited in the surface cavity such that it atleast partially covers (or in some instances, completely covers) the ICand the second set of wires that connect the IC to the substrate. Duringdeposition, the sidewalls of the surface cavity confine theencapsulating material to within the cavity, and reduce the risk of theencapsulating material coming in contact with the MEMS transducer orother components on the substrate. The deposited encapsulating materialcan be given time to settle into a steady state with regard to flowwithin the surface cavity. If in the steady state, portions of the IC orthe second set of wires remain exposed, additional encapsulatingmaterial can be added. The encapsulating material can then be cooleduntil it solidifies.

It should be noted that process stages in the process 900 depicted inFIG. 9 can be performed in an order different from the one shown in FIG.9. For example, mounting the IC in the surface cavity (stage 908) can becarried out before mounting the MEMS transducer on the substrate (stage906). Further, installation of the wires between the IC and the MEMStransducer and the IC and the substrate (stage 910) can be carried outin any order.

FIGS. 10A and 10B depict a cross-sectional view and a top view,respectively, of a ninth example microphone device 1000 according to anembodiment of the present disclosure. In the ninth example microphonedevice 1000 shown in FIGS. 10A and 10B, a encapsulating materialconfinement structure includes a surface cavity 1020 formed by a wall1026 that rises or protrudes above a front surface 1022 of the substrate1002. The wall 1026 has a top surface 1040 that is positioned at aheight H5 above the front surface 1022 of the substrate 1002. The heightH5 can be greater than, equal to, or less than a height of the IC 104. Aperiphery 1042 of the wall 1026 defines an edge of the surface cavity1020. The IC 104 is mounted on a mounting surface 1024 that is a portionof the front surface 1022 of the substrate 1002. The MEMS transducer 102is also mounted on the front surface 1022 of the substrate 1002. Thus,the IC 104 and the MEMS transducer 102 are mounted on coplanar surfaceportions of the substrate 1002.

The encapsulating material 1008 is deposited within the surface cavity1020 and at least partially covers the IC 104 and at least partiallycovers the second set of wires 125. In one or more embodiments, theencapsulating material 1008 completely covers the IC 104 and the secondset of wires 125. In one or more embodiments, the encapsulating material1008 completely covers the IC 104, while at least partially covering thesecond set of wires 125.

The wall 1026 can completely surround the IC 104 and a portion of thefront surface 1022 of the substrate 1002. In one or more embodiments,the wall 1026 can be discontinuous. In one or more embodiments, the wall1026 may not entirely surround the IC 104. For example, the wall 1026may extend between the MEMS transducer 102 and the IC 104, so as toreduce the risk of the encapsulating material 1008 making contact withthe MEMS transducer 102 during and after deposition. In one or moreembodiments, the wall 1026 can be incorporated in the seventh and theeighth example microphone devices 700 and 800 discussed above inrelation to FIGS. 7A-8. In some embodiments, the top surface 1040 can beconsidered a top or front surface of the substrate, such that the cavityis formed in part or in whole as an area surrounded by the wall 1026. Insome implementations, ninth example microphone device 1000 can includeICs in addition to the IC 104. In some such implementations, theencapsulating material 1008 can cover partially or completely all of theICs and the wires connecting those ICs to the substrate 1002.

FIG. 11 shows a flow diagram of an example process 1100 formanufacturing a microphone device according to an embodiment of thepresent disclosure. In particular, the process 1100 can be utilized formanufacturing the third example microphone device discussed above inrelation to FIGS. 10A and 10B, in some embodiments. The process 1100includes providing a substrate having a wall formed on a front surfaceof the substrate, where the wall forms an surface cavity (stage 1102);mounting a MEMS transducer on the substrate (stage 1104), mounting an ICon an IC mounting surface in the surface cavity (stage 1106), installinga first set of bonding wires between the IC and the MEMS transducer, anda second set of wires between the IC and the substrate (stage 1108), anddepositing an encapsulation material into the surface cavity to at leastpartially cover (or in some instances, completely cover) the IC and thesecond set of wires (stage 1110).

The process 1100 includes providing a substrate having a wall formed ona front surface of the substrate, where the wall forms an surface cavity(stage 1102). On example of this process stage is discussed above inrelation to FIGS. 10A and 10B, where the wall 1026 forms an surfacecavity 1020 on the substrate 1002. In one or more embodiments, the wall1026 can be formed of the same material as the substrate. For example,the wall can be formed by depositing additional layers of the substratematerial. In one or more embodiments, the wall can be formed using asolder mask, a solder stop mask, or a solder resist. Multiple layers ofthe solder mask can be deposited around the IC in the desired pattern toform the wall. Stages 1104-1110 can be performed in a manner similar tothat discussed above in relation to stages 906-912. It should be notedthat the order of stages described herein is provided by way of exampleonly, and the present disclosure is not limited to any particular orderof performing the stages. For example, in some embodiments, the MEMStransducer may be mounted prior to mounting of the IC, while in otherembodiments, the IC may be mounted prior to mounting of the MEMStransducer.

Various example embodiments discussed herein can provide substantialadvantages over existing designs, such as substrate-embedded ICpackages. In such packages, the IC is completely surrounded by thesubstrate material, and is embedded inside the substrate during themanufacturing process of the substrate. However, embedding the IC insidethe substrate raises overall cost of the microphone device. For example,defects in substrate can cause a good IC embedded in the defectedsubstrate to be discarded along with the defected substrate. Further,there is an increased burden in the design phase to finalize the designsof the IC and the substrate early in the manufacturing process becauseof the additional lead-time needed to embed the IC into the substrate.Further, the inventory of ICs is held up inside the substrate. Variousembodiments discussed herein, on the other hand, allow the microphonedevice to be manufactured with established substrate and semiconductorprocesses, as the IC is encapsulated after the manufacture of thesubstrate. Moreover, the IC inventory is not held up during themanufacture of the substrate. This reduces the complexity of themanufacturing process of an encapsulated IC and reduces the time tomarket.

FIG. 12 shows a cross-sectional view of a tenth example microphonedevice 1200. The tenth example microphone device 1200 is similar in manyrespects to the second example microphone device 200 discussed above inrelation to FIG. 2. To the extent that some features of the tenthexample microphone device 1200 are similar to those of the secondexample microphone device 200, such features are provided with the samereference numerals in both FIGS. 2 and 12. The tenth example microphonedevice 1200 includes at least one wall 1226 positioned on the frontsurface 116 of the substrate between the MEMS transducer 102 and thefirst and second ICs 104 and 106. The wall 1226 can be similar to thewall 1026 discussed above in relation to the ninth example microphonedevice 1000 shown in FIGS. 10A and 10B, and can define a surface cavity1220. In one or more embodiments, the wall 1226 can be discontinuous,and may be disposed only between the MEMS transducer 102 and the firstand second ICs 104 and 106.

While the above discussion describes various embodiments, each havingvarious features, it is understood that features described in oneembodiment, can be incorporated in other embodiments as well. Forinstance, the first example microphone device 100 shown in FIG. 1 caninclude one or more features of each of the example microphone devicesdiscussed in relation to FIGS. 2-12. For example, the first examplemicrophone device 100 can include, without limitation, one or more ofthe encapsulating material 132 (FIG. 2), a thin region 134 (FIG. 2), asealed port 140 (FIG. 3), a die attach film 142 (FIG. 3), a multilayeredsubstrate 410 (FIGS. 4A and 4B), a particulate filter (also referred toas “a particulate barrier”) 502, a cover bonding ring 650 with a notch652 (FIGS. 6A and 6B), a surface cavity 750 (FIG. 7A), a surface cavity820 (FIG. 8), a wall 1026 (FIG. 10A), and a wall 1226 (FIG. 12).

The second example microphone device 200 shown in FIG. 2 can include oneor more features of each of the example microphone devices discussed inrelation to FIGS. 1, 3-12. For example, the second example microphonedevice 200 can include, without limitation, one or more of a sealed port140 (FIG. 3), a die attach film 142 (FIG. 3), a multilayered substrate410 (FIGS. 4A and 4B), a particulate filter 502, a cover bonding ring650 with a notch 652 (FIGS. 6A and 6B), a surface cavity 750 (FIG. 7A),a surface cavity 820 (FIG. 8), a wall 1026 (FIG. 10A), and a wall 1226(FIG. 12).

The third example microphone device 300 shown in FIG. 3 can include oneor more features of each of the example microphone devices discussedabove in relation to FIGS. 1-2, 4-12. For example, the third examplemicrophone device 300 can include, without limitation, one or more of amultilayered substrate 410 (FIGS. 4A and 4B), a particulate filter 502,a cover bonding ring 650 with a notch 652 (FIGS. 6A and 6B), a surfacecavity 750 (FIG. 7A), a surface cavity 820 (FIG. 8), a wall 1026 (FIG.10A), and a wall 1226 (FIG. 12).

The fourth example microphone device 400 shown in FIGS. 4A and 4B caninclude one or more features of each of the example microphone devicesdiscussed above in relation to FIGS. 1-3, 5-12. For example, the fourthexample microphone device 400 can include, without limitation, one ormore of a die attach film 142 (FIG. 3), a particulate filter 502 (FIG.5), a cover bonding ring 650 with a notch 652 (FIGS. 6A and 6B), asurface cavity 750 (FIG. 7A), a surface cavity 820 (FIG. 8), a wall 1026(FIG. 10A), and a wall 1226 (FIG. 12).

The fifth example microphone device 500 shown in FIG. 5 can include oneor more features of each of the example microphone devices discussedabove in relation to FIGS. 1-4B, 6A-12. For example, the fifth examplemicrophone device 500 can include, without limitation, one or more of asealed port 140 (FIG. 3), a die attach film 142 (FIG. 3), a multilayeredsubstrate 410 (FIGS. 4A and 4B), a cover bonding ring 650 with a notch652 (FIGS. 6A and 6B), a surface cavity 750 (FIG. 7A), a surface cavity820 (FIG. 8), a wall 1026 (FIG. 10A), and a wall 1226 (FIG. 12).

The sixth example microphone device 600 shown in FIGS. 6A and 6B caninclude one or more features of each of the example microphone devicesdiscussed above in relation to FIGS. 1-5, 7A-12. For example, the sixthexample microphone device 600 can include, without limitation, one ormore of an encapsulating material 132 (FIG. 2), a thin region 134 (FIG.2), a sealed port 140 (FIG. 3), a die attach film 142 (FIG. 3), amultilayered substrate 410 (FIGS. 4A and 4B), a particulate filter 502(FIG. 5), a surface cavity 750 (FIG. 7A), a surface cavity 820 (FIG. 8),a wall 1026 (FIG. 10A), and a wall 1226 (FIG. 12).

The seventh example microphone device 700 shown in FIGS. 7A-7C caninclude one or more features of each of the example microphone devicesdiscussed above in relation to FIGS. 1-6B, 8-12. For example, theseventh example microphone device 700 can include, without limitation,one or more of a die attach film 142 (FIG. 3), a multilayered substrate410 (FIGS. 4A and 4B), a particulate filter 502 (FIG. 5), a coverbonding ring 650 with a notch 652 (FIGS. 6A and 6B), a surface cavity820 (FIG. 8), a wall 1026 (FIG. 10A), and a wall 1226 (FIG. 12).

The eighth example microphone device 800 shown in FIG. 8 can include oneor more features of each of the example microphone devices discussedabove in relation to FIGS. 1-7C, 9-12. For example, the eighth examplemicrophone device 800 can include, without limitation, one or more of adie attach film 142 (FIG. 3), a multilayered substrate 410 (FIGS. 4A and4B), a particulate filter 502 (FIG. 5), a cover bonding ring 650 with anotch 652 (FIGS. 6A and 6B), multiple ICs 104 and 106 (FIG. 7C), asurface cavity 750 (FIG. 7A), a wall 1026 (FIG. 10A), and a wall 1226(FIG. 12).

The ninth example microphone device 1000 shown in FIGS. 10A and 10B caninclude one or more features of each of the example microphone devicesdiscussed in relation to FIGS. 1-9, and 12. For example, the ninthexample microphone device 1000 can include, without limitation, one ormore of a die attach film 142 (FIG. 3), a multilayered substrate 410(FIGS. 4A and 4B), a particulate filter 502 (FIG. 5), a cover bondingring 650 with a notch 652 (FIGS. 6A and 6B), multiple ICs 104 and 106(FIG. 7C), a surface cavity 750 (FIG. 7A), and a surface cavity 820(FIG. 8).

The tenth example microphone device 1200 shown in FIG. 12 can includeone or more features of each of the example microphone devices discussedin relation to FIGS. 1-11. For example, the tenth example microphonedevice 1200 can include, without limitation, one or more of a sealedport 140 (FIG. 3), a die attach film 142 (FIG. 3), a multilayeredsubstrate 410 (FIGS. 4A and 4B), a particulate filter 502, a coverbonding ring 650 with a notch 652 (FIGS. 6A and 6B), a surface cavity750 (FIG. 7A), and a surface cavity 820 (FIG. 8).

The herein described subject matter sometimes illustrates differentcomponents contained within, or connected with, different othercomponents. It is to be understood that such depicted architectures areillustrative, and that in fact many other architectures can beimplemented which achieve the same functionality. In a conceptual sense,any arrangement of components to achieve the same functionality iseffectively “associated” such that the desired functionality isachieved. Hence, any two components herein combined to achieve aparticular functionality can be seen as “associated with” each othersuch that the desired functionality is achieved, irrespective ofarchitectures or intermedial components. Likewise, any two components soassociated can also be viewed as being “operably connected,” or“operably coupled,” to each other to achieve the desired functionality,and any two components capable of being so associated can also be viewedas being “operably couplable,” to each other to achieve the desiredfunctionality. Specific examples of operably couplable include but arenot limited to physically mateable and/or physically interactingcomponents and/or wirelessly interactable and/or wirelessly interactingcomponents and/or logically interacting and/or logically interactablecomponents.

With respect to the use of plural and/or singular terms herein, thosehaving skill in the art can translate from the plural to the singularand/or from the singular to the plural as is appropriate to the contextand/or application. The various singular/plural permutations may beexpressly set forth herein for sake of clarity.

It will be understood by those within the art that, in general, termsused herein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.).

It will be further understood by those within the art that if a specificnumber of an introduced claim recitation is intended, such an intentwill be explicitly recited in the claim, and in the absence of suchrecitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to inventions containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should typically be interpreted to mean “atleast one” or “one or more”); the same holds true for the use ofdefinite articles used to introduce claim recitations. In addition, evenif a specific number of an introduced claim recitation is explicitlyrecited, those skilled in the art will recognize that such recitationshould typically be interpreted to mean at least the recited number(e.g., the bare recitation of “two recitations,” without othermodifiers, typically means at least two recitations, or two or morerecitations).

Furthermore, in those instances where a convention analogous to “atleast one of A, B, and C, etc.” is used, in general such a constructionis intended in the sense one having skill in the art would understandthe convention (e.g., “a system having at least one of A, B, and C”would include but not be limited to systems that have A alone, B alone,C alone, A and B together, A and C together, B and C together, and/or A,B, and C together, etc.). In those instances where a conventionanalogous to “at least one of A, B, or C, etc.” is used, in general sucha construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, or C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that virtually any disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms. For example, the phrase “A or B” will be understood toinclude the possibilities of “A” or “B” or “A and B.” Further, unlessotherwise noted, the use of the words “approximate,” “about,” “around,”“substantially,” etc., mean plus or minus ten percent.

The foregoing description of illustrative embodiments has been presentedfor purposes of illustration and of description. It is not intended tobe exhaustive or limiting with respect to the precise form disclosed,and modifications and variations are possible in light of the aboveteachings or may be acquired from practice of the disclosed embodiments.It is intended that the scope of the invention be defined by the claimsappended hereto and their equivalents.

What is claimed is:
 1. A microphone device, comprising: a housingincluding a substrate and a cover disposed over the substrate, thehousing including a sound port between the interior of the housing andthe exterior of the housing; a microelectromechanical systems (MEMS)transducer and an integrated circuit (IC) positioned within the housingand mounted on a common surface of the housing, the MEMS transducerelectrically connected to the IC, and the IC electrically connected to aconductor on the substrate; an encapsulating material covering the IC;and an encapsulating material confinement structure disposed between theMEMS transducer and the IC, wherein the encapsulating materialconfinement structure at least partially confines the encapsulatingmaterial around the IC.
 2. The microphone device of claim 1, wherein theencapsulating material completely covers the IC.
 3. The microphonedevice of claim 1, wherein the encapsulating material confinementstructure includes a wall portion disposed between the MEMS transducerand the IC.
 4. The microphone device of claim 3, wherein the substrateis the common surface of the housing, wherein the MEMS transducer andthe IC are mounted on coplanar surface portions of the substrate,wherein the wall portion protrudes above the coplanar surface portionsof the substrate and the encapsulating material is at least partiallyconfined by the wall portion.
 5. The microphone device of claim 4,wherein the wall portion is a discrete member disposed on the substrate.6. The microphone device of claim 3, wherein the wall portion is formedof a different material than the substrate.
 7. The microphone device ofclaim 3, wherein the wall portion completely surrounds the IC.
 8. Themicrophone device of claim 3, wherein the substrate is the commonsurface of the housing, wherein the substrate defines a cavity includingan IC mounting surface portion on which the IC is mounted, the wallportion forming a portion of the cavity, wherein the MEMS transducer ismounted on a MEMS mounting surface portion of the substrate, the MEMSmounting surface portion elevated relative to the IC mounting surfaceportion, wherein the encapsulating material is at least partiallyconfined in the cavity.
 9. The microphone device of claim 8, wherein thecover is mounted on a cover mounting surface portion of the substrate,and the MEMS mounting surface portion is raised above the cover mountingsurface portion of the substrate, and the cover mounting surface portionof the substrate is raised above the IC mounting surface portion. 10.The microphone device of claim 8, wherein the cover is mounted on acover mounting surface portion of the substrate, and the MEMS mountingsurface portion and the cover mounting surface portion are coplanar. 11.The microphone device of claim 8, wherein the MEMS mounting surfaceportion is a platform that completely surrounds the entire periphery ofthe cavity.
 12. The microphone device of claim 1, wherein the ICincludes two ICs covered by the encapsulating material.
 13. Themicrophone device of claim 1, wherein the IC is a flip-chip mounted onthe substrate.
 14. The microphone device of claim 1, further comprising:a set of wires interconnecting the IC to the conductor on the substrate,the set of wires at least partially covered by the encapsulatingmaterial; a cavity disposed in the substrate and including a wallportion forming the encapsulating material confinement structure, thecavity including an IC mounting surface portion on which the IC ismounted, wherein the encapsulating material is at least partiallyconfined by the cavity.
 15. The microphone device of claim 1, furthercomprising: a set of wires interconnecting the IC to the conductor onthe substrate, the set of wires at least partially covered by theencapsulating material; the encapsulating material confinement structureincluding a wall portion disposed between the MEMS transducer and theIC, and the MEMS transducer and the IC mounted on coplanar surfaceportions of the substrate, wherein the encapsulating material is atleast partially confined by the wall portion.
 16. The microphone deviceof claim 1, wherein the encapsulating material comprises epoxy.
 17. Themicrophone device of claim 1, further comprising an electricallyconductive heat shield at least partially covering the IC.
 18. Themicrophone device of claim 17, wherein the electrically conductive heatshield is disposed between a first layer of the encapsulating materialand a second layer of the encapsulating material.
 19. The microphonedevice of claim 17, wherein the electrically conductive heat shield iselectrically connected to a ground plane disposed on the substrate. 20.The microphone device of claim 1, wherein the sound port is positionedin the substrate.